The following is the description of the role of the deacon at Mass from the General Instruction of the Roman Missal:
The Eucharistic sacrifice of the Mass is the action of Christ (GIRM 11) and of God's people, in which the human race adores the Father, through Christ, in the Holy Spirit (16), and the faithful join themselves to Christ in giving thanks and in acknowledging the great things God has done (78). The Mass is the 'sacrament of unity" (91, 92) in which the faithful are nourished from the table of God's Word and of Christ's Body (28). This unity is expressed particularly in common posture (42), in communal singing (47), reverential silence (45, 56), and in sharing together of the one bread and one cup (83, 321). The assumption of the Roman Missal is that every Sunday and feast day, the Eucharistic liturgy will be celebrated with song (40, 115), with a cantor (104), with one or two readers (109), and with other assisting ministers (115). It is also assumed that all communicants present at Mass, priest celebrant, deacon, ministers and all in the assembly, will receive the sacrament from bread and wine consecrated at that Mass (85, 281, 321), just as the priest celebrant must do (85, 243). The liturgical books, particularly those used by the priest celebrant, the deacon and the assisting ministers should be beautiful and appropriate to the celebration (349) rather than being disposable pages or booklets.
The foundational principles explaining the purpose of the parts of the Mass are found primarily in Chapter II (27-90) and this chapter provides the basis for the more detailed norms found in Chapter IV (112-287). Chapters V (188-318) and VI (319-351) also give general principles regarding the arrangement of the church and the requisites for Mass.
The rubrics assume that the celebration of Mass will take place in a church (288) with a freestanding altar (299), an ambo for proclaiming God's Word (309), and a presidential chair used by the priest at certain points during the celebration (310). Although the tabernacle may be located in the sanctuary (315b), all the rubrics assume that it is located in a chapel apart from the sanctuary since they make no reference to it when describing the actions of the priest celebrant and other ministers during Mass. If, however, the tabernacle is located in the sanctuary, all the ministers genuflect to it only when they first approach the altar and when they leave the sanctuary, but not during the celebration of Mass itself (274).
After the priest, in virtue of the sacred ordination he has received, the deacon has first place among those who minister in the celebration of the Eucharist. For the sacred order of the diaconate has been held in high honor in the Church since the time of the Apostles. (1) At Mass the deacon proclaims the Gospel reading, sometimes preaches God's Word, announces the intentions of the General Intercessions, ministers to the priest, prepares the altar and serves the celebration of the sacrifice, distributes the Eucharist to the faithful, especially under the species of wine, and from time to time gives directions regarding the people's gestures and posture (GIRM, 94).
Mass with a Deacon
When there is a deacon present at the Eucharistic celebration, he should exercise his ministry wearing sacred vestments. (1) The deacon:
- assists the priest and processes at his side (unless he is carrying the Book of the Gospels, in which case, he precedes the priest);
- ministers the chalice or the book (Roman Missal) at the altar;
- proclaims the Gospel and, at the request of the priest celebrant, may preach the homily (see GIRM no. 55);
- gives timely directions to the faithful and announces the intentions in the General Intercessions;
- assists the priest celebrant in distributing Communion, especially as minister of the Precious Blood, and cleanses and arranges the sacred vessels;
- as needed, performs the offices of other ministers when none of them are present (GIRM, 171).
- Vested and carrying the Book of the Gospels slightly elevated, the deacon precedes the priest on the way to the altar or else walks at the priest's side if the Book of the Gospels is already enshrined on the altar (172).
- Upon arriving at the altar, if he is carrying the Book of the Gospels, the deacon omits the reverence and goes up to the altar.
- After placing the Book of the Gospels on it, along with the priest, he venerates the altar with a kiss. However, if he is not carrying the Book of the Gospels, he customarily makes a profound bow to the altar with the priest alone, and then with him venerates the altar with a kiss. If, however, the tabernacle is located in the sanctuary, all the ministers genuflect to it only when they first approach the altar and when they leave the sanctuary, but not during the celebration of Mass itself (274). Finally, if incense is used, he assists the priest in putting some in the censer and incensing the cross and the altar (173).
- After the incensation, the deacon goes to the chair with the priest, sits next to him, and assists him as required (GIRM, no. 174).
Liturgy of the Word
- If incense is used, the deacon assists the priest when he puts incense in the censer during the singing of the Alleluia or other chant.
- Then he makes a profound bow before the priest and asks for the blessing, saying in a low voice: "Father, give me your blessing." The priest blesses him: "The Lord be in your heart …." The deacon signs himself with the sign of the cross and responds: Amen.
- Then he takes the Book of the Gospels which was fittingly laid on the altar and, with a bow to the altar, processes to the ambo, slightly elevating the book, with the censer bearer preceding him, while the censer is smoking, and with ministers holding lighted candles.
- There he greets the people, saying, with his hands joined: "The Lord be with you," and then, "A reading from the Holy Gospel …" signing the book with his thumb and afterwards, himself on his forehead, mouth and breast.
He incenses the book and proclaims the Gospel reading.
- After the reading, he acclaims without raising the Book of the Gospels: "The Gospel of the Lord," to which all respond: "Praise to you, Lord Jesus Christ."
- Then he venerates the book with a kiss and the deacon says inaudibly: "Through the words of the gospel may our sins be washed away." He then returns the book to the priest or places it in another suitable place.
When the deacon is assisting a Bishop, he may carry the book to him to be kissed.
- In more solemn celebrations, as circumstances allow, the Bishop may impart a blessing to the people with the Book of the Gospels.
Then the deacon carries the Book of the Gospels to the side table or another dignified and appropriate place (175). If there is no other qualified reader present, then the deacon may deliver the other readings as well (176). However, every effort should be made to insure the presence of lectors for the celebration of the Eucharistic liturgy.
- After the priest introduces the General Intercessions, the deacon announces the intentions from the ambo or another suitable place (177). He remains at the ambo while the priest concludes the General Intercessions with a prayer.
- At the conclusion of this prayer, the deacon begins the preparation of the altar.
Liturgy of the Eucharist
- After the General Intercessions, while the priest remains at the chair, the deacon prepares the altar, assisted by the acolyte(s), but the care of the sacred vessels belongs to the deacon. He assists the priest in receiving the people's gifts in a suitable place.
- Next, he hands the priest the paten with the bread to be consecrated, pours wine and a little water into the chalice saying inaudibly: "By the mystery of this water and wine …," then passes the chalice to the priest.
- He may also make this preparation of the chalice at the side table.
- If incense is used, the deacon assists the priest with the incensation of the gifts, the cross and the altar; afterward he, or the acolyte, incenses the priest and the people (178).
- During the Eucharistic Prayer, the deacon stands near but slightly behind the priest, so that when needed he may assist the priest with the chalice or the Roman Missal.
- As a general rule, from the epiclesis until the elevation of the chalice the deacon remains kneeling.* If there are several deacons present, one of them goes to place incense in the censer for the consecration and then incenses at the elevation of the host and the chalice (179).
- At the final doxology of the Eucharistic Prayer, the deacon stands next to the priest, and after the priest (or Bishop) hands him the chalice, he elevates the chalice as the priest raises the paten with the Eucharistic bread, until the people have responded with the acclamation Amen (180).
- After the priest has said the prayer for peace and the greeting "The peace of the Lord be with you always" and the people have made the response "And also with you," the deacon may invite all to exchange the sign of peace, saying, with hands joined and facing the people: Let us offer one another a sign of peace. He himself receives the sign of peace from the priest and may offer it to the other ministers near him (181).
- After the priest's communion, the deacon receives under both kinds from the priest himself and then assists the priest in giving communion to the people. But if communion is given under both kinds, the deacon ministers the chalice.
- When the distribution is completed, the deacon immediately and reverently consumes at the altar all of the Blood of Christ which remains; he may be assisted, if needs dictate, by other deacons and priests (182) or, in their absence, by Extraordinary Ministers of Holy Communion (Norms for the Distribution and Reception of Holy Communion in the Dioceses of the United States of America, no. 37).
- After communion, the deacon returns to the altar with the priest and collects any remaining fragments. He then takes the chalice and other vessels to the side table, where he cleanses them and arranges them in the usual way; the priest returns to the chair. But it is permissible to leave the vessels to be cleansed, suitably covered and at a side table on a corporal, immediately after Mass following the dismissal of the people (183).
- Following the Prayer after Communion, if there are any brief announcements, the deacon may make them, unless the priest prefers to do so himself (184).
- If a more solemn formula for the blessing is used, or even a prayer over the people, the deacon says: "Bow your heads and pray for God's blessing."
- After the priest's blessing, the deacon, with hands joined and facing the people, dismisses them, saying: "Go in the peace of Christ" or using one of the other formulas of the Roman Missal (185).
- Along with the priest, the deacon venerates the altar with a kiss, makes a profound bow, (2) and leaves in the manner prescribed for the entrance procession (186).
(1) See Paul VI, Apostolic Letter, Sacrum diaconatus ordinem, AAS 59 (1967), 697-704; Roman Pontifical, De Ordinatione Episcopi, presbyterorum et diaconarum, editio typica altera, 1989, no. 173.
(2) If there is a tabernacle in the sanctuary, all genuflect.
*This practice has been adapted for the Archdiocese of Los Angeles; the deacon stands during the Eucharistic Prayer.